Current seat recliners commonly rely upon a limited choice of mechanisms for seat back angle adjustment. One common mechanism uses a pawl engaging a toothed rack, for example. Another common mechanism uses a threaded rod engaging a nut. Further, a clutch member that is positionable along a rod is also common.
The implementations of these devises are typically relatively bulky or expensive, however, especially when in the form of a recliner for a restraint seat. More particularly, a restraint seat has passenger restraint belts fastened or anchored directly to the restraint seat structure, rather than to a vehicle structure. Thus the restraint seat carries the restraint loads, whereas a non-restraint seat does not. This in turn demands a stronger structure in the restraint seat, including each of its components.
Applicant""s prior U.S. Pat. No. 5,597,205 (which is incorporated by reference) discloses an energy absorbing restraint seat back recliner that provides a screw driven high strength recliner mechanism that provides an infinite position adjustment in a high strength construction that is appropriate for a single-sided or dual-sided application in a restraint seat. The drawback with a screw driven mechanism, however, is that the recline can be slow.
An object of the present invention is to provide a cost effective quick adjustment mechanism for a screw drive recliner that is strong enough for single-sided restraint seat applications.
The present invention comprises a quick adjustment mechanism for a lead screw operated seat back recliner that is appropriate for use in a restraint safety seat where the seat belt is mounted to the seat. In the automotive seat safety restraint recliner of the present invention, upper and lower body members are connected respectively to back frame and seat frame portions of the seat and are pivotally connected together to vary the inclination of the back frame with respect to the seat frame. The movement of the body members is accomplished by a rotation mechanism that operates a screw drive mechanism having axially spaced fixed and traveling pinions mounted on a lead screw. The fixed pinion is mounted to one body member and the traveling pinion is mounted to the other body member, such that rotation of the lead screw causes relative axial movement of the pinions that in turn produces a change in seat back inclination. The improvement of the present invention comprises a quick adjustment mechanism wherein one of the pinions, desirably the fixed pinion, is mounted in a multiple position quick adjustment slot in the body member. The pinion has a laterally extending mounting pin that engages the slot. The slot has a plurality of spaced transverse portions that extend transversely to the axial direction of the screw and the axial direction of the mounting pin. The pin fits in each transverse portion, each transverse portion having a transverse edge that engages the pin and resists movement of the pin in the body member when an axial force is placed on the pin by the lead screw. The transverse portions are spaced such that the back frame is at a different inclination when the pin is in each transverse portion. The transverse portions are connected by an offset quick adjustment channel of the slot such that the pin can be moved from one transverse portion to another by moving the pin into the quick adjustment channel and then into another transverse channel. The seat is capable of further inclination adjustment by rotation of the lead screw while the pin is in any of the transverse portions of the slot.
Desirably, the quick adjustment slot comprises a downwardly facing U-shaped slot wherein legs of the slot comprise the transverse portions of the slot and the portion connecting the legs of the slot comprises the quick adjustment channel. The distal or outermost leg of the slot extends down and around the solid center portion between the legs of the slot such that the pinion pin nests securely at the bottom of the leg when an axial stress is placed on the lead screw.
The rotation means for rotating the lead screw can be manual or motorized and is mounted to the lead screw for movement therewith as the lead screw is moved to reposition the pinion pin in different transverse portions of the quick adjustment slot.
The multiple position guide slot of the quick adjustment mechanism is desirably at the front of the recliner body. This front guide slot works with a forward pivot block and provides a quick recline selection independent of the fine recliner adjustment discussed above. The quick recliner does not compromise collision safety, however. Rather, collision integrity is maintained because the two position guide slot resists impact movement and limits travel in the same manner as discussed above regarding the fine recline adjustment safety slot in the lower recliner body.
These and other features, objects, and benefits of the invention will be recognized by one having ordinary skill in the art and by those who practice the invention, from the specification, the claims, and the drawing figures.